Elevator cars are conventionally formed to comprise a load-bearing frame structure, which is often referred to as a car sling, as well as a cabin box wherein the passengers and the goods are to be transported. Typically, the frame comprises a beam structure forming a rigid base frame on which components forming the cabin box are mounted. The components of the cabin box, typically at least the walls, the ceiling and the floor are typically fixed to each other such that a self-standing box-like structure is formed. The box-like structure is mounted to rest on top of the frame. Suspension of the car is provided via said frame by suspending the frame with ropes connected to the frame. The ropes are not directly connected to the cabin box and thus the cabin can be formed light-weighted whereas the frame is formed robust. The frame is typically shaped in accordance with the intended type of suspension. The frame can be such that it has a horizontal lower cross beam structure below the cabin box and a horizontal upper cross beam structure above the cabin box, and further upright beam structures on opposite sides of the cabin box connecting the upper and lower cross beam structure rigidly to each other. This is the most common structure for the frame structure, but of course, the frame can also be formed to have some alternative shape. In case the suspension is from top of the car, the frame typically comprises a horizontal upper cross beam structure above the cabin box where the suspension ropes are connected either by fixing the ends thereto or by passing under diverting pulleys mounted on the cross beam structure. In case the suspension is from bottom of the car, the frame typically comprises at least a horizontal lower cross beam structure below the cabin box where the suspension ropes are connected by passing under diverting pulleys mounted on the cross beam structure.
For various reasons, such as for increasing ride comfort, it is in some cases advantageous to isolate the cabin and the frame from each other such that they are not rigidly connected to each other in vertical direction. By isolating the cabin and frame with elastic members mounted between them, it can be achieved advantages in terms of ride comfort as well as service life of the car components, in particular guide means of the elevator car, such as guide rollers of guide sliders. In this way, vibrations can be reduced, for instance.
A drawback has been that the final car structure has not been adequately well balanced. Although a lot of work has been done for balancing the frame and the cabin box, the cabin box is often anyway in tilted position on the car due to the components, such as decoration panels and/or the toe guard, which are after the balancing locally supplied for the car. It has been noticed that this is because the isolated car has not been properly balanced on the site. This has caused that the ride comfort, especially with high-rise elevators, is heavily influenced by the static and dynamic balancing of the sling-cabin system. The compression of the elastic members between the cabin and the frame have been uneven, whereby the cabin travels in a tilted position. The tilted position of the cabin has triggered vibrations in itself, and these vibrations have been amplified by inertia and misalignments of the guide rails, for instance. For these reasons, a need for improved balancing of the car has come up.